mySVGExternalResourcesRequired.externalResourcesRequired in SVG 1.1

Documents often reference and use the contents of other files (and other Web resources) as part of their rendering. In some cases, authors want to specify that particular resources are required for a document to be considered correct.

This property is available on all container elements and to all elements which potentially can reference external resources. It specifies whether referenced resources that are not part of the current document are required for proper rendering of the given container element or graphics element.

This property is not inheritable (from a sense of attribute value inheritance), but if set on a container element, its value will apply to all elements within the container.

As a read-only SVGAnimatedBoolean, this property cannot be directly set or read. Instead, for UAs supporting this property, you would use code like...

myElement.externalResourcesRequired.baseVal=true

...to set the value directly. For UAs which don't support this property, you might try:

myElement.setAttribute('externalResourcesRequired','true')

(Despite officially being an SVGAnimatedBoolean and not a plain Boolean, this property is not able to be animated. As noted in the SVG 1.1 DOM interface for SVGExternalResourcesRequired, making it an SVGAnimatedBoolean was a mistake kept on only for backwards compatibility. The baseVal and animVal properties of this property will always be the same.)

The default value for this property is false, which indicates that resources external to the current document are optional. Document rendering can proceed even if external resources are unavailable to the current element and its descendants.

Setting a value of true indicates that resources external to the current document are required. If an external resource is not available, progressive rendering is suspended, the document's SVGLoad event (onload) is not fired and the animation timeline does not begin until that resource and all other required resources become available, have been parsed and are ready to be rendered. If a timeout event occurs on a required resource, then the document goes into an error state (see Error processing). The document remains in an error state until all required resources become available.